Compressor unloader



11 F. VAN D. LoNGAcRE COMPRESSOR UNLOADER Filed Junel8, 1926 s Sheets-Sheet 1 v INVENTOR icauickmL I r acre Jan. 11, 1927.

F. VAN D. LONGACRE COMPRESSOR UNLOADER Filed June 18, 1926 3 Sheets-Sheet 2 INVENTOR 'cklZDLo arm BY m5 ATTOR Jan. '11, 1 927.

F. VAN D. LONGACRE COMPRESSOR UNLOADER Filed June 18, 1926 3 Sheets-Sheet 5 INVENTOR wade wield/0L awe BY m5 ATTORNIIE Patented Jan. 11, 1927.,

UNITED STAT S PATENT-OFFICE.

FREDERICK VAN Dl'JZIElIR,,LONGACRE, OF YONKERS, NEW YORK, ASSIGNOR TO INGEB- SOLL-RAND COMPANY,

JERSEY.

Application filed June 18,

This invention relates to compressor unloaders for compound compressors and the objects of the invention are to enable the cooler pressures to be automatically maintained at or closely approximate to the mosteconomical pressure for complete compression in two or more stages to any predetermined final discharge-pressure.

The regulation of the output is preferably effected by devices automatically responsive to variatlons in discharge pressure, while the regulation of the intermediate pressures is preferably effected by devices automatically responsive to variations in the cooler ressures themselves, although the invention 1s not to be understood as limited to this precise form of regulation.

Another object of the invention is to automatically preventnthe operation of each succeeding regulating device until the next preceding regulating device has operated at least partially, so that the cylinders are un-- loaded successively and in proper order.

- The invention is shown in one of its preferred forms in the accompanying drawings, in which Figure 1 is a' diagrammatic representation partly in horizontal section showing the invention applied to a three-stage compressor,

Figure 2 is an enlar ed longitudinal sectional elevation taken through the regulator for the low pressure cylinder, and Figure 3 is an enlarged longitudinal sectional elevation taken through one of the regulators for the intermediate and high pressure cylinders.

Referring to the drawings, the three cylinders A, B and C of a three stage compressor shown for purposes of illustration are provided with the pistons D and inlet and discharge valves E and F in the usual manner. First and second intercoolers G and H are connected between the cylinders and the inlet of the compressor is indicated at J and the discharge K is connected by the pipe L to a receiver 0- In the present instance the invention is shown applied to a compressor having a plurality of clearance chambers P, in this instance four clearance chambers being shown for-each cylinder, controlled by the clear-L ance valves Q, operating in the clearance valve cylinders R on each of the compressor cylinders in the usual manner, it being coiugnnsson nNLoAnER.

1926'. Serial No. 116,909. t

understood that the clearance valves Q are held closed by the application 10f pressure fluid to the cylinders R and maybe assisted in opening by'springstnot shown); Each cylinder is provided with its own automatic regulator A, B and C and in accordance with this invention each regulator automatically controls the unloading and loading of its respective cylinder in successive steps. The regulator A is preferably automatically responsive to receiver pressure from the pipe S connecting the receiver 0 with the regulator A at the point T and' communicating with a di'aphragmchamber U, shown in Figure 2, having the diaphragm V- which controls the movement of the weighted lever W having the auxiliary valve X connected thereto, which in turn controls the movements of the main 0 crating valves Y in the regulator casing These main operating valves Y in turn control the su ply and release of receiver pressure from tl ie connection a' at the diaphragm chamber. U to "and through the pipe connections 1, 2, 3 and 4 respectively which are adapted to be connected as indicated in the drawings to the unloader valve cylinders R.

The auxiliary valve X of the regulator A is normally in its lowermost'position as indicated in Figure 2 and is raised step by step by predetermined increase in receiver pressure beneath the diaphragm V which causes the main valvesY to operate one after another from the bottom upwards to unload the cylinder 'A step by step and load the cylinder by 0 eration of the main valves Y in reverse or er. K I

The regulators B and C for the intermediate and high pressure cylinders B and C are constructed alike and are indicated in detail in Figure 3. Each of these regulators B and C are preferably automatically responsive to intercooler pressures in the first and second intercoolers G and H respec tively through the ipes b and a connected to the diaphragm c ambers U of-the regulators The auxiliary valves X of the regu-' lators B and C" are normally in raised po-v sition as indicated in Figure 3 and these regulators are automatically responsive to I;

drop in the intercooler pressures so that as the auxiliary valves X move downward','the

main operating valves Y are actuated one after the other fromthe top downward to control the supply and release of intercooler pressure from the diaphragm chamber connection d to and through the pipes 1, 2, 3 and 4 adapted to be connected to the unloader valve cylinders R ofthe cylinders B and C respectively as indicated in the drawings. As the auxiliary valves X of the intermediate and high pressure regulators B andC move upwardly, the cylinders B and C are loaded step by step.

Referring mdre particularly to Figures 1 and 2, the spaces 6 between the heads f and g of the main operating valves Y of the regulator A are constantly open to receiver pressure from theconnection a through the ports .h. and each ofthe valves Y is provided with a shoe j controlling the ports k and 0 so that when the valves Y are in the right hand positions, as indicated in Figure 2, receiver pressure passes to all of the pipes 1, 2, 3 and 4 and all of the unloader valves are held closed. As the valves Y are moved successively to their left'hand positions, the pipes 1, 2, 3, and 4 are opened one'after the other to atmosphere through the ports g, since the ports is and 0 Will be connected y the shoes Automatic connections controlled by the auxiliary valve X are provided for .alternately supplying receiver pressure to the heads 7 and g of the valves. Y to actuate said valves. The receiver pipe g is connected .to the valve casing r of the auxiliary valve X and the passage 8 leads to a point between the valve heads t and u so that the space between said valve heads is constantly subject to receiver pressure. The ends 1) and in of the valve chamber a: are open to atmosphere. and passages 5, 6, 7, and 8 connect the left hand heads f of the valves Y with the central portion of the valve chamber a: as shown. Passages9, 10, 11 and 12 connect the opposite heads 9 of the valves Y with the valve chamber a: so that when the valve X is in the position indicated-in F i'gure 2, passages 5, 6, 7 and 8 are all subject to receiver pressure while the passages 9, 10, 11 and 12 are all open to atmosphere. By means of the ports and passages shown, the valves Y are successively operated for the purposes described.

I The regulators B andC are constructed in a similar mannerto the regulator A with the exception that the space e between the heads of the valves Y are constantly open to intercooler pressure' through the connection d and the ports h and the passages 5, 6, 7 and 8 and the passages 9, 10, 11 and, 12 are so connected to the valve chamber a: of the auxiliary valve X that the valves Y are successively operated from the top downwards as the auxiliary valve X moves downward step by step, due to a drop in cooler pressure, for unloading the intermediate and high pressure cylinders step by step -pressure cylinder takes place.

and for loading the cylinders as the auxiliary valve X moves upwardly.

Instead of connecting the receiver'pipe' (1 directly to the auxiliary valve casings 1' of the regulators B and C, I prefer to place an automatic interlocking or controlling valve in each of these connections, so that the regulator B is rendered inoperative until the first regulator A for the low pressure cylinder has operated, and similarly the regulator C cannot operate until the preceding regulator B for the intermediate compressor 0 linder B has operated. Any suitable inter ocking valves or change valves as they may be called may be provided for this purpose and such change valves may be connected in any suitable location in the pipe systems, but I. have indicated these valves in the receiver connections (1 for the regulators B and C as a suitable and convenient location.

As shown, these interlocking or change valves comprise a cylinder 13 having a valve 14 therein provided with the heads.15 and 16 controlling the ports 17 and 18. branch from the pipe 9 is connected through the change valve at the ports 17 and 18 to the casing r of the au'xiliaryvalve X. A spring 19 tends to force the interlocking valve 14 to-a position to open the ports 17 and 18 and a port 20 in the bushing 21 of the change valve for the regulator B is connected by the pipe 22 with the unloader valve pipe 1 of the preceding regulator A which is the regulator for the low pres sure cylinder. Similarly, the port 20 of the change valve for the regulator C is connected by the pipe-22 with the unloader valve pipe 1 of the preceding regulator B for the intermediate pressure cylinder B.

With all the unloader valves Q of'the low pressure cylinder closed and subject to receiver pressure through the pipes 1, 2, 3,

and 4, there will obviously be receiver pressure in the pipe 22 and the change valve 14 will be held to its right hand position against the tension of the spring 19 so that receiver A pressurewill be cut ofi from the regulator B and said regulator will be inoperative until the first step of unloading for thelow The pipes 1 and 22 connected to the regulator A will then be opened to atmosphere and the change valve 14 will operate to supply receiver pressure through the pipe q for the operation of the main valves of the intermediate regulator B, 7

Similarly the regulator C remains inoperative until the first step of unloading of the intermediate pressure cylinder B has been effected by the regulator B. By the means described, the succe in regulators B and'C cannot operate unti the immeregulator has at least par- 7 diate preceding tially operated.

i the pressure to be maintained in the first cooler G is to be 16 lbs. as indicated, and that the pressure in the second cooler H is to be 50 lbs. for most economic operation.. A

predetermined increase of receiver pressure will cause the auxiliary valve X ofthe regulator A to rise a suflicient' distance to open the passage 5 of the regulator to atmosphere and place the passage 9 'in communication Avith the receiver pipe 9 so that the first valve Y of the regulator will be actuated and the pipes 1 and 22 will be opened to atmosphere through the port 7. The unloader valve Q of the cylinder A to which pipe 1 is connected will open for the first step of unloading. The change valve 14 will be moved to opened position by the spring 19 owing to the release of receiver pressure against the head 15 of the valve and the regulator B is in a condition to operate for unloading purposes in case the pressure of the cooler G falls a predetermined amount. \Vhen this occurs and the first stepof unloading of the cylinder B takes place, the

regulator C will be placed in condition for.

operation and will operate to unload the cylinder C upon a predetermined decrease of pressure in thesecond cooler H.

I claim: 1. In a multi-stage compressor, the com bination of cylinders and inlet and discharge valves, intercoolers and a receiver, means au-- tomatically responsive to use 111 receiver pressure for unloading the low pressure cylinder, unloading means for each of the other cylinders automatically responsive to drop in the intercooler pressures respectively, and means for automatically preventing the operation of each of the unloading devices subject to intercooler pressure until the unloadingdevice for. the low pressure cylinder has operated.

2. In a multitage compressor, the com-. bination of cylinders and inlet and discharge valves, intercoolers and a receiver, means automatically,responsive to rise in receiver pressure for unloading the low pressure cylinder, unloading means for each of the other cylinders automatically responsive to drop in the intercooler pressures respectively, and

.-means for automatically and successively preventing the operation of each of the unloading devices for the intermediate and high pressure cylinders until the next preceding unloading device has operated.

3. In a. compound compressor, the combination of hi h and low pressure cylinders, inlet and disc arge valves therefor, an intercooler, a plurality of clearance chambers and unloading valves for each cylinder for step by step unloadingand loading, means automatically responsive to rise in discharge cooler, a plurality of clearance chambers and unloading valves for each cylinder for step by step unloading and loading, means automatically responsive to rise in discharge pressure for unloading the low pressure cylinder, means automatically responsive to drop in intercooler pressure for unloading the high pressure cylinder, and means for automatically preventing the operation of the unloading device forthe high pressure cylinder until the unloading devicefor the iow pressure cylinder has operated.

5. In a multi-stage compressor, the combination of cylinders and inlet "and discharge valves, intercoolers and a receiver, a plurality of clearance chambers and unloading valves for each cylinder for step by step unloading and loading, means automatically responsive to rise in receiver pressure for unloading. the low pressure cylinder, and unloading means for each of the other cylinders automatically responsive to drop in the intercooler pressures respectively.

6. In a multi-stage compressor, the combination of cylinders and inlet and discharge valves, intercoolers and a receiver, a plurality of clearance chambers and unloading valves for each cylinder for 'step by step unloading and loading, means automatically responsive to rise in receiver pressure for unloading the low pressure cylinder, unloading means for each of the other cylinders automatically responsive to drop in the intercooler pressures respectively, and means for automatically preventing the operation of each of the unloading devices subject to intel-cooler pressure until the unloading device for the low pressure cylinder has operated.

7. In a multi-stage compressor, the combination of cylinders and inlet and discharge valves, intercoolers and a receiver, a plurality of clearance. chambers and unloading valves for each cylinder for step by step unloading and loading, means automatically responsive to rise in receiver pressure for unloading the low pressure cylinder, unloading means for each of the other cylinders automatically responsive to drop in the intercooler pressures respectively, and means for automatically andsuccessively preventing the operation of each of the unloading devices for the intermediate and high pressure cylinders until the next preceding unloading device has operated.

In testimony whereof I have signed this specificatiom FREDERICK van DUZER LONGACRE. 

